Oregon Revised Statutes Probate Law § 112.285

(1) A will may be revoked or altered by another will.

(2) A will may be revoked by one or more physical acts by being burned, torn, canceled, obliterated or destroyed, with the intent and purpose of the testator of revoking the will, by the testator, or by another person at the direction of the testator and in the presence of the testator. The injury or destruction of the will by a person other than the testator at the direction and in the presence of the testator shall be proved by at least two witnesses.

(3) A partial revocation of a provision in a will by one or more physical acts as described in subsection (2) of this section is not a valid revocation. One or more physical acts that affect one or more provisions of a will but not the entirety of the will are not effective to revoke those provisions, but clear and convincing evidence may show that the testator intended by the physical act or acts to revoke the entirety of the will.